Present OSHA enforced federal decompression schedules for compressed air and caisson workers produce a 25 percent incidence of aseptic necrosis at pressures over 36 psig and an unacceptable incidence of decompression sickness at lower pressures. We propose to computer generate a new set of air decompression tables using the AUTODEC computer system which has gained acceptance and use in the commercial diving field. The present tables will be analyzed and compared with Naval and other decompression schedules using the AUTODEC computer. Additionally, whole body nitrogen wash-out studies will be carried out to determine the amount of residual nitrogen present after decompression once the present tables is complete. During decompression, ultrasonic scanning of selected body tissues will be used to quantitate stationary bubble formation in the body during decompression. When baseline data have been gathered on nitrogen wash-out and static bubble formation for the present OSHA tables, the new computer generated tables will be similarly analyzed. Modifications will be made in decompression profiles and length of stops as required to minimize gross bubble formation and this will be cross-checked with whole body nitrogen elimination measurements. After appropriate modification, a complete set of new decompression schedules will be generated for air decompression and also decompression using oxygen. Additionally, the effects of daily exposure for a 5-day work week will be analyzed in terms of nitrogen accumulation from shift to shift, its effect on bubble formation and total nitrogen wash-out at the end of the work week. Using these methods, it can be assured that the new tables will be superior to the present ones and more positive assurance can be given that the dangers of aseptic necrosis have been lessened while minimizing risk of decompression sickness or other complications in test subjects.